Au lait means with milk.
An example of au lait is a shot of coffee served with warm milk, which is called cafe au lait.
"au lait." YourDictionary, n.d. Web. 15 May 2018. <http://www.yourdictionary.com/au-lait>.
au lait. (n.d.). Retrieved May 15th, 2018, from http://www.yourdictionary.com/au-lait
Origin of au lait